One of the attackers started punching the 48-year-old woman. The attack then moved inside the home, where the teens continued punching her with their fists and hitting her with chairs, among other things.

Police say the beating happened near 12th and Morton Streets Tuesday around 9 p.m. in Chester. The suspects are 16 and 17 years of age.

The victim suffered cuts and bruises on her face but did not get medical help, according to police.

Len Worby, one of the victim's neighbors, told the Delco Times the attack was the second in two weeks.

“She got beat up about two weeks ago,” Worby told the newspaper. “Someone hit her over the head with a gun.”

A local parent saw the video on Facebook Thursday morning and tipped off police.

Police say they tracked down four of the teenage girls in the video. Two of those arrested are sisters, according to the Delco Times. The Associated Press reported they were charged as adults with aggravated assault, reckless endangerment, burglary and harassment.

"The parents are upset," one of the officers told the Times. "The girls are defiant. It's like they didn't do anything wrong."

Investigators say they're searching for two more girls who they believe were involved.

"Their behavior is animalistic to this poor woman," Delaware County District Attorney Jack Whelan told the Times. "We are going to aggressively prosecute each of them for their callous indifference to this woman."